Research On Preparation Of Functional Polymer Electrolyte Based On Electrospinning Technology

People developed solid-state batteries with solid-state electrolytes to solve safety problems of traditional liquid electrolyte lithium-ion batteries(LIBs).Compared with inorganic solid electrolytes,the problem of solid polymer electrolytes is that the conductivity under room temperature is low,so how to improve its room temperature conductivity is the focus of its research.Functionalization is one of the solutions.At present,the electrospinning method has been widely studied due to its high porosity,strong operability,and wide range of materials to choose from,and it can also perform multi-component functional compounding through the design of its nozzle.Therefore,in this thesis,the electrospinning method is used as the preparation method to study the functionalization of the diaphragm and the polymer electrolyte.Specifically include the following:(1)PVDF-HFP@CCS@PFR composite separator is prepared by single-nozzle electrospinning technology.In this work,electrospinning PVDF-HFP is used to explore the influence of parameters on its fibers,and then the electrospinning and hot pressing technology PVDF-HFP layer is used to improve the adhesion between the ceramic separator and the electrode,thereby improving the battery’s performance of cycle stability.After 200 cycles,the capacity retention rate is increased from 80%to 88%.(2)Coaxial electrospinning method to produce single ion conductor polymer electrolyte with high thermal stability.The coaxial electrospinning technology is used to realize the compounding of the two components of the core-shell fibers.The PI@PPSLi membrane prepared by this technology has extremely high porosity and high ionic conductivity of 1.70×10-5 S/cm and its migration number can reach 0.76,and there will be no significant size shrinkage at 190℃,it also exhibits good cycle performance and rate performance.(3)Single-ion conductor solid polymer electrolyte produced by multi-nozzle electrospinning method.In this work,based on the investigation of the parameters in the first electrospinning work,the multi-nozzle electrospinning technology and heat treatment are used to construct a solid-state ion conduction pathway with a threedimensional interpenetrating network structure,and this structure is beneficial to inhibit the separation of the two components.The PAS/PS membrane prepared by us has a migration number of 0.96 at 60℃ and an ionic conductivity of 5.4×10-5 S·cm-1.The method can also balance the composition ratio by controlling the number of spinning nozzles with different compositions,so as to adjust the performance of the solid polymer electrolyte.